Natural frequency vibrating conveyer



E. J. RENNER IATURAL FREQUENCY VIBRATING CONVEYER Jan. 5, 1954 2 Sheets-Sheet l Filed May 24, 1950 INVENTOR.

Jan. 5, 1954 E. J. RENNER NATURAL FREQUENCY VIBRATING CONVEYER 2 Sheets-Sheet 2 Filed May 24, 1950 INVENTOR.

Patented Jan. 5, 19,54

serena-ruwweg vincente conve c y,

Elmer Aurore, winmx to: Stephens-Adams@ Mfg- Cf,l

IllinlififiL Applicatian May 24, 195o, serial No. 164,014 3 Claims. (Ql- 18S-:2,20*

The principal object of this invention is to convey loose, discrete material in a substantial-ly continuous, wavy stream along a trayv or table.

Generally speaking, this is accomplished by pivotally connecting a tray and a counterbalance for substantial parallel motion cnopposite sides of supporting fulcra, interposing harmonic spring elements between them, and giving one of them harmonic vibration whereby the tray is given balanced vibration in substantially the natural period of harmonic spring elements.

Further objects and advantages of the invens tion will appear as the disclosure proceeds and the description is read in connection with the accompanying diagrammatic drawings, in which:

Fig. 1 is a side elevation of one embodiment of the invention;

Fig. 2 is a longitudinal central vertical section of the left end portion of Fig. l;

Fig. 3 is an end view looking from the right in Fig. 1;

Fig. 4 is a section on the line 4,-.-4 of 2;

Fig. 5 is an axial section through one of the pivotal connections; Y

Fig. 6 is a side elevation of another embodiment of the invention;

Fig. '7 is an enlarged side elevation of one unit shown in Fig. 6 arranged to incline the tray at a slight angle;

Fig. 8 is a plan View of a carrier support used in Figs. 6 and 7; and

Fig. 9 is a sketch indicating how the spr-lng units I6 vibrate at the end portions and leave the middle practically neutral.

The tray' l0 and counterbalance II are connected by four links or levers I2 pivoted at opposite ends to the tray and the c'ounterbalance and fulcrumed between them at I3 in bearings supported by brackets I4 on a base frame I5, This gives the tray and the counterbalance parallel motion in moving toward and away from each other while the levers swing on the fulcra.

The tray and the counterbalance are connected by spring elements, here shown as helical springs I6 aligned longitudinally with the tray and the counterbalance and inclined with respect to the tray and the counterbalance.

Harmonic motion is given to the tray by a connecting rod I1 pivoted to the tray I0 at I8 on its center line and driven by an eccentric I9 on a shaft 20, in turn driven by a motor 2| through a belt 22 and suitable pulleys.

The essential assembly of the tray and counterf balance, mounted on the rocking arms or links after the fashion of parallel motion and connected by helical springs, whichr resist any change in tliedistence between them. Seemsl to be the` nub ofthe apparatus. The harmonic drive of; the eccentric forces the: balanced units apart. then together at each revolution: and; during each 0i which the helical. springs one: resistance in both directions. The timing of the drive fits in with the natural period QI vibration of the Springs @mi develops. a harmonie action inthe end nortions of the Springs. leaving the intermediate or Prtieally middle portion neutral (Fig. 9). Each time the throw of the eccentric moves the tray, the springs are compressed or` extended with harmanie motion, which tends, flo-reverse itself in time with the rotation of the. eccentric.

This arrangement gives the desired vibratory movement to the tray andthe counterbalance (which may also be a tray-for motivering` the Inaterial). and does so with a minimum of power input.

The pivots, 24 between the ends of the links or levers II and the tray and counterbalance are preferably in substantially the form shown in Fig. 5. Actually, the pivoting is about a shaft 26 having a shoulder 21, a bearing portion 28, and a threaded portion 29 at each end. The bearing portion is received within a hollow bearing portion II). at the end of each link or lever. Those bearing portions are spaced radially to receive rubber blocks 3| of double truste-:conical shape, compressed between those bearing portions and between disks 2,4 by e nut 35. Thus, the actual bearing is on rubber under compression, and the rotary motion between the pivots and the shaft is of suchy relatively small angularity that the energy absorption is very low, although the rubber does do some work in resisting any relative movement between the tray andthe counterbaiance. and tending to always return them to normal position. A

iEhe, bearings of the` fulcro I3 are about a shaft Il and are of the Same character as that show-n in Fig. 5, but appropriately larger because those bearings must carry the entire weight of both the tray, the counterbalance, the links, and the springs, etc.

Each end of each spring I 6 is fitted with a cylindrical block 40 of rubber of durometer hardness on the order of 1I). which is compressed between disks 4I having curved edges 42, and drawn together by a bolt and a nut 43. Compression of the blocks 40 shortens themin the middle area M, but extends them circumferentially in the area 45 within the end convolutions 46 of the spring I6. This has the effect of a yieldable connection between the bolts 43 and the ends of the springs.

Spring assemblies of that order are made up to length and assembled with the tray and the counterbalance by projecting portions of the bolts 43 extending through openings 41 in brackets 48 fixed to the tray and the counterbalance respectively. They are made fast by nuts 49 which clamp the brackets against the outer disks 4I'. This connection between the springs and the tray and the counterbalance gives the spring elements between the brackets 46 a definite length, and at the same time gives the spacing between the tray and the counterbalance a definite 1ength.

Any change in the spacing requires a change in the effective length of the spring elements; and, when coupled with harmonic motion, the effect is as above described.

While the features here disclosed will be varied according to the circumstances and individual preferences, a design that has been found satisfactory has the following dimensions:

The tray is 10 feet long and concave upwardly; 14 inches wide inside on a radius of 7% inches. The counterbalance is 8 feet and 6 inches long; 1 foot 21/2 inches wide. The frame is 11 feet 319-6 inches long; 1 foot 9 inches wide, inside. The links or levers I2 are 1 foot 1/8 inch long between centers. The eccentric is 1% of an inch off center and 1.4375 inches in diameter. The motor is 1A hp., 1660 R. P. M., and the drive gives the eccentric 815 R. P. M. This combination produces a conveying speed of 75 F. P. M.

In the embodiment shown in Figs. 6, 7 and 8, the base frame I5 is replaced by two carrier supports, generally indicated by 50 and 5I. The carrier support 56 is a relatively short, forked frame having brackets 52 at the front end to receive the fulcra of the levers I2 in bearings 53, and having a platform 54 on which the power unit is mounted. The carrier supports 5I are composed mainly of brackets 55 having bearings 56 for the shaft I2 and cross connected in any suitable manner to hold them together.

Both of the carrier supports are equipped with rubber feet 51.

The carrier supports merely act as supports and do not have to be tied together or fastened down. They require very much less material than the base frame I5 and cost less to manufacture.

The embodiment shown in Figs. 6 and 7 includes separate units, indicated generally by 60 and 6I, connected together by boltsand fianges, generally indicated at 62. In this way, the'conveyor can be made to any suitable length.

The units 6l) are shown without power", although they could be so equipped. Unit 6| is identical with 50 except it is equipped with a power drive. Two or three non-powered units may be connected by the bolted flange 62 to one powered unit to give a conveyor length of 30 to 40 feet. Longer units can be made by inserting power units at every fourth section, thus continuing the conveyor to any desired length.

Conveyors embodying the invention will handle any sort of discrete material and it has been found that they will convey finely powdered or pulverulent materials. By inclining lthe tray two or more degrees, substantially as illustrated in Fig. 7, finely powdered materials will flow as a liquid down the tray, probably because it becomes iiuent with the mixture of air.

The inclination is here produced by providing the power unit 50 with feet 63 and 64 of different height, but the inclination can be worked out in various ways.

While two springs I6 are shown in all the forms here illustrated, one, or any plurality of springs, may be used according to the circumstances.

I claim:

1. In a vibrating conveyor, a conveyor tray element, a balancing element spaced from the tray element, rigid levers having their opposite ends pivotally connected to said elements and fulcrumed between them on a fixed support, means for vibrating said elements, and helical spring means having its opposite ends directly connected to the tray element and balancing element and being unstressed at mid-stroke and acting alternately in compression and tension during each half cycle.

2. In a vibrating conveyor, a conveyor tray element, a balancing element spaced from the tray element, rigid levers having their opposite ends pivotally connected to said elements and fulcrurned between them on a fixed support, helical spring means having its opposite ends directly connected to the tray element and balancing element, and means for vibrating said elements at the natural frequency of said helical spring means, said helical spring means being unstressed at mid-stroke and acting alternately in compression and tension during each half cycle.

3. In a vibrating conveyor, a conveyor tray element, a balancing element spaced from the tray element, rigid levers having their opposite ends pivotally connected to said elements and fulcrumed between them on a fixed support means for vibrating said elements, and helical spring means diagonally disposed between said elements and having its opposite ends directly connected to the tray element and balancing element and being unstressed at mid-stroke and acting alternately in compression and tension during each half cycle.

ELMER. J. RENNER.

Germany July 22, 1937 

